1. Field of the Invention
The present invention relates to a lid body portion and an electronic device package using the lid body portion and an electronic device.
2. Description of Related Art
In recent years, the electronic device is required to be reduced in size and height (thinned and low in height) as well as required to be highly functional.
In general, the electronic device is formed by housing an electronic device component performing a given function in an electronic device package. The electronic device package houses the electronic device component by covering part or all of a circuit substrate on which the electronic device is mounted with a lid body having a space portion.
Due to the request of reducing the size and the height of the electronic device, the space in which the electronic device component is housed inside the electronic device package is limited.
In order to mount electronic device components having many functions as many as possible or in order to mount an electronic device components having a large size due to many functions for realizing high functions of the electronic device under the space limitation, it is necessary to improve a mounting ratio of the electronic device component (the area of the electronic device component/the package area, namely, a ratio of the area of the electronic device component with respect to the area in which the electronic device component can be mounted inside the electronic device package).
Then, in order to improve the mounting ratio inside the electronic device package, a novel structure is necessary in the electronic device package.
As a structure of a related-art electronic device package, a resin-sealed package type in which a bottom surface (bottom portion) of a die pad supporting a semiconductor device is exposed is disclosed in FIG. 1 of JP-A-2011-66327 (Patent Literature 1).
In the resin-sealed package type in which the bottom surface of the die pad is exposed, an electronic device in which the size of each edge is 0.44 mm×0.44 mm is supported by the die pad in an electric device package in which the size of each edge is 0.8 mm×0.8 mm and the thickness is 0.3 mm, and the mounting ratio of the electric device component is approximately 30%.
As another structure of the electronic device package, there is a structure in which an internal electrode is provided in a base portion of a package base formed by stacking single-layer flat plates using a glass or ceramic-based material, the internal electrode is connected to an external electrode provided on a bottom surface of the base portion through a lead-wire path and the base portion is covered with a lid body.
As a related-art example of the lid body covering the base portion (a package type of the lid body covering the base portion), an example in which a glass or ceramic-based material is applied to the lid body is disclosed in Japanese Patent No. 4630110 (Patent Literature 2).
Specifically, as shown in FIG. 7, the structure of a lid body type 101 using the glass or ceramic-based material includes a flat-plate shaped base portion 103, a lid body portion 102 made of a glass or ceramic-based material and covering the base portion 103 and a bonding member 108 bonding the base portion 103 to the lid portion 102.
As the structure of the lid-body type 101 is a structure in which the above components such as an inner lead, the die pad and an outer lead are integrated into the base portion 103, the number of components included in the package is small and the electronic device component can be efficiently housed in an internal space 104 of the lid body 102.
As a related-art example of the lid body covering the base portion, examples in which a metallic material is applied to the lid body are disclosed in JP-A-6-132766 (Patent Literature 3) or JP-A-2010-278498 (Patent Literature 4).
Detailed explanation of the related-art example will be given. As shown in FIG. 8, the size relation in the structure of the internal space 104 of the lid body portion 102 in the case of the metallic lid body type is represented by a flat surface length L1 by a corner portion 114 having a curvature radius, a flat surface length L2 by a side-plate inner surface 110 having a tapered surface directed to the inside and a flat surface length L3 by a corner 115 where the side-plate inner surface 110 crosses a flange-portion flat surface 107 of the lid body portion 102.
However, in the resin-sealed package type disclosed in Patent Literature 1, the volume of the device component which can occupy the volume of the electronic device package is reduced. In particular, the mounting ratio of electronic device component occupying the package is reduced as the reduction in size and height proceeds.
Specifically, as space for arranging components such as the inner lead, the die pad and the outer lead at intervals are necessary inside the package, the ratio in which these components occupy the package volume is high, which reduces the mounting ratio of the electronic device components in the package size.
In the package of the lid-body type made of a glass or ceramic-based material disclosed in Patent Literature 2, the corner portion 114 inside the lid body portion 102 has the curvature radius in the internal space 104 of the lid body portion 102.
Then, the side-plate inner surface 110 of the lid body portion 102 has a tapered surface 110 directed to the inside of the internal space 104. Accordingly, the corner portion 114 and the side-plate inner surface 110 may contact the electronic device component, therefore, it is necessary to keep a distance from the flat surface (direction) length L1 of the corner portion 114 and the flat surface length L2 of the side-plate inner surface 110, which will be a constraint for enlarging the size of the electronic device component to be mounted.
Accordingly, it has been difficult to improve the mounting ratio of electronic device component. Additionally, there is a limit for reducing the height by uniformly thinning a thickness T3 of the lid body portion 102 made of a glass or ceramic-based material.
As the related-art example of the package type having the structure of the lid-body type made of a metal disclosed in Patent Literatures 3 and 4 has the size relation shown in FIG. 8, there is a danger that the inside (the side-plate inner surface 110 having the tapered surface directed to the inside and so on) of the lid body portion 102 contacts the electronic device component. It is generally necessary that the inside of the lid body portion 102 keeps a distance from the electronic device component and so on, which has been the constraint for enlarging the size of the electronic device component to be mounted. Accordingly, it has been difficult to improve the mounting ratio of electronic device component.